Stainless Steel finishing

Discussion in 'Finishing Techniques' started by bettinanissen, May 8, 2010.

  1. bettinanissen
    bettinanissen New Member
    hi everyone,

    I have just received my first order of a stainless steel ring and the surface is quite rough. As i am new to stainless steel printing i would like to know how other people are finishing their metal parts.

    i started using a dremel to smooth the surface but my design is very detailed and some areas therefore hard to reach. is there an easier way to get everything nice and smooth (and silver)? or would metal casting be a better option if i need a very smooth surface?
  2. GlenG
    GlenG New Member
    There is no question that the SS material is difficult to smooth and polish. This is partly due to the fact that it is a composite metal. The stainless component is alloy 420 and as printed, it has a high surface hardness. The bronze component is soft and abrades at a different rate than the stainless. This creates additional problems if you are trying to achieve a mirror finish. Under a microscope the partially polished surface will appear as having tiny pock marks. This is due to the uneven surface hardness. However it is possible to get a polished finish. It just takes a lot of time and careful attention. I use carbide grinding burs to remove the rough print lines(bark) on a raw print. Then i use a progression of abrasives beginning with 180-220 grit down to 400-600 grit. At this point the surface is almost polished. If mirror bright is required now is the time to switch to polishing compunds
    The absolute best and fastest finishing materials are those containing diamond. Inexpensive diamond coated grinding pins come in a variety of shapes and sizes. These will fit the chuck on your Dremel. I often use these after carbide burs. They can get into very small places. Other diamond materials come in the form of sanding sheets, made by 3M company. I believe the trade name is Micro Diamond Film. Another option would be diamond polishing pastes. These are used on small felt wheels that can also be mounted on your Dremel. These pastes range from relatively coarse 180 grit down to amazinly fine 2-3000 mesh! Overall these materials are somewhat more costly than traditional abrasives but they work better, faster, and longer than aluminum oxide, silicon carbide etc. They require a lot less hand pressure and will save you time, pain and money in the long run.
    In the end, this material will never be the same as Sterling or Karat Gold. But, if you learn to work within the boundaries of the SS print medium amazing things will result. Dam the torpedoes, full speed ahead.

  3. bettinanissen
    bettinanissen New Member
    Thank you Glen for the detailed reply. Sounds really helpful. I will try your suggestions and get back here with my progress (haven't yet started)! Thanks!

    Still wondering if sandblasting would work though?
  4. GlenG
    GlenG New Member
    Hi Bett,
    Sandblasting is not a good way to remove rough textures. Because the abrasive attacks the high spots and the low spots equally. For instance, if you have a smooth sheet of metal with a deep scratch in it, sandblasting will magnify the scratch!
    We have a super high pressure blaster at the shop, it is powerful enough to remove hard metal. But we only use it to remove support media and tiny metal particles that sometime stick to raw prints. We also have a lower powered "bead blaster" this we use after a piece is polished to give a soft matte surface.

    I know it is a real pain to polish things but when you work on a small scale and you want it done right............... that's what hands are for.
    Post a picture of your design and I can probably advise a specific finishing strategy for you. I'm not sure where you are located but a good source for jewelry supplies and metal finishing tools is the Gesswein Co. located in Connecticut, USA. They have an amazing array of tools and supplies, the best I have ever seen.